"Darren's going to be a free agent and there's been communication with his agent," McKenzie said, per ESPN.com. "He's going to see what his market is. And that's the thing, when you're talking about the games that he's missed, he has no idea -- and when I say 'He,' I'm talking about his agent -- he has no idea what his market value will be and I couldn't tell you what the other 31 teams think."

The trouble for the 26-year-old McFadden is staying healthy. McFadden appeared in just 10 games in 2013, and he missed 19 of the Raiders' past 41 games and 29 in his six-year career. He has never played more than 13 games in any NFL season.

In his 10 games in 2013, McFadden was less than spectacular, rushing for just 379 yards with a paltry 3.3 yards-per-carry average. It marked McFadden's second consecutive mediocre season.

McKenzie said he would like to keep free-agent running back Rashad Jennings. The 28-year-old Jennings showed more burst and the ability to create creases in his first season in Oakland. Taking over the starting role, Jennings galloped for 733 yards and six touchdowns. He missed one game due to a concussion.

Depending on how the market shakes out, Jennings could be both the better runner and cheaper option for the Raiders.